Wafer demount receptable for separation of thinned wafer from mounting carrier

ABSTRACT

A wafer demounting receptacle comprises a substantially circular plate member and an upstanding rim structure provided around a periphery of the plate member. The rim structure is stepped and includes a first step defining a first diameter, and a second step defining a second diameter grater than the first diameter. The riser of the first step has a very low height so that a gap between the plate member and a fragile semiconductor wafer bonded to a carrier having a peripheral abutment surface resting on the run of the first step, limits the bending of an edge portion of the wafer in a direction towards the plate member while the wafer is partially demounted from a wafer carrier. The plate member is further provided with a pattern of holes that generates eddy currents in a solvent that flows over the wafer, carrier, and receptacle so as to soften and dissolve the mounting adhesive between the wafer and carrier such that the wafer is separated from the carrier. The wafer demount receptacle can be used in conjunction with a wafer demount tool comprising a chamber defined between a backing plate and a contact plate. The chamber is provided with a gas inlet for introducing a pressurized gas, while the contact plate is provided with a plurality of through-holes. The wafer demount tool is mated to the wafer demount receptacle such that the contact plate is juxtaposed against the back side of a wafer carrier resting in the wafer demount receptacle. Pressurized gas flowing through the wafer demount tool displaces solvent from the wafer-carrier interface to further promote separation of the wafer from the carrier.

RELATED APPLICATIONS

This application is a Divisional of U.S. application No. 09/776,758,filed on Feb. 6, 2001, whose contents are incorporated in theirentirety, by reference thereto. Now U.S. Pat. No. 6,491,083

This application is also related to U.S. application Ser. No.09/776,922, filed on Feb. 6, 2001, entitled “Wafer Demount GasDistribution Tool”, now U.S. Pat. No. 6,470,946.

TECHNICAL FIELD

The present invention is directed to the field of equipment andaccessories for processing semiconductor wafers. More particularly, itis directed to a receptacle and tool which are used to demount asemiconductor wafer from a carrier following one or more steps in amanufacturing operation.

BACKGROUND OF THE INVENTION

During semiconductor manufacture, a semiconductor wafer undergoes anumber of processing steps where it is exposed to potentially aggressiveconditions including, but not limited to, chemical and physical contact,pressure, and temperature. These conditions may be deleterious to thefeatures contained on the wafer or to the wafer itself. For example, theprocess of thinning a wafer for packaging, either by chemical orphysical means, can result in wafer fracture. It is common, therefore,to mount the wafer to a carrier which provides support and stability tothe wafer during processing. An adhesive means is commonly used to bondthe wafer to the carrier to prevent slippage.

A wafer can be mounted to a carrier and retained in a number of ways.FIGS. 1a-1 c show a semiconductor wafer partially adhered to a carrierby different adhesive means. FIG. 1a shows a wafer partially adheredusing an adhesive layer such as epoxy or tape. FIG. 1b shows a waferpartially adhered using molecular Van der Waals forces. FIG. 1c shows awafer partially adhered using a remote vacuum source. In each of theseexamples, the wafer exhibits a measurable deflection or strain due tothe force of gravity acting on the unsupported area of the wafer. If thedeflection exceeds a certain critical value, which depends on certainphysical properties of the wafer, the wafer will fracture.

At the conclusion of a series of wafer processing steps the wafer mustbe debonded from the carrier. The debonding of the wafer must be donewith care so as to avoid fracturing the wafer. The prior art includes anumber of devices which can be used to demount a wafer from a surface.Typically these devices involve mechanical means that may impart damageto the wafer. Examples of wafer demounting devices include tweezers,blades, or vacuum wands.

Other devices have been developed which are less intrusive to the wafer.U.S. Pat. No. 5,952,242 to Pietsch discloses a means for removing asemiconductor wafer from a flat substrate in which liquid is used tolift the semiconductor wafer from the substrate. The fixture includes acylindrical removal head which is mounted on a carrier disc andsurrounds a wafer mounted thereon. The cylindrical removal head isprovided with circumferential U-shaped grooves on an inner surfacethereof to accommodate blocking devices which capture the wafer once ithas been dislodged from the carrier disc. In this example, the wafer ismerely resting on the carrier disc and is not adhered to the carrier byan adhesive means.

U.S. Pat. No. 4,466,852 to Beltz et al. discloses an apparatus andmethod for dislodging a wafer from a carrier by forcing a liquid througha channel passing through the disc. The liquid impinges on a backsurface of the wafer at a point that is off-center so as to apply aleveraged force for loosening the wafer. The disclosure states that anoperator manually catches the wafer as it is dislodged.

U.S. Pat. No. 4,949,783 to Lakios et al. discloses a substrate transportand cooling apparatus. Forced convection is provided by a gas flowinginto the area between a substrate and a cooling fixture at a pressurehigh enough to cause bowing or lifting of the substrate and thus tocreate a gas region between the substrate and the fixture. An O-ringnear the periphery of the substrate substantially seals the gas fromentering a processing chamber. The gas flow into and through the areabetween the substrate and cooling fixture absorbs heat from, and therebycools the substrate.

U.S. Pat. No. 5,632,847 to Ohno et al. discloses a method for removing afilm from a substrate comprising injecting ozone in to an acid aqueoussolution, and bringing bubbles formed by the ozone injection intocontact with the film. When the ozone of each bubble is brought intocontact with the film on the substrate, an intermediate between ozoneand the film is formed, and then the formed intermediate is removed fromthe substrate by the acid aqueous solution of each bubble.

During the manufacture of gallium arsenide (GaAs) wafers, the wafer istypically bonded to a carrier. As seen in FIG. 2a, carrier 150 has acircular shape with an overall diameter s1. The carrier 150 is dividedinto two overall portions, an annular peripheral surface 152 of width s3and a wafer support surface 154 having a radius s2.

The support region is populated with a pattern of through-holes 162.FIG. 2b shows the carrier 150 having a semiconductor wafer 170 adheredthereto by means of an adhesive 172. The wafer 170 is mounted on the topsurface 174 of the carrier 150 at the wafer support surface 154, therebyleaving the peripheral surface 152 exposed. The carrier also has a backsurface 176.

Given the brittleness of the semiconductor wafer 170 and the carrier150, it is a challenge to dismount the wafer 170 from the carrier 150without damaging either.

SUMMARY OF THE INVENTION

One device in accordance with the present invention comprises a waferdemount receptacle for removing a semiconductor wafer from a mountingcarrier. The wafer demount receptacle includes a plate member thatcontains a pattern of through holes. The perimeter of the plate membercomprises an upstanding rim structure which is stepped and includes afirst step associated with a first riser and a first run, and a secondstep associated with a second riser. The run of the first step is shapedand sized to accommodate by abutment, a peripheral portion of a wafercarrier, to which a semiconductor wafer is bonded. When resting on therun of the first step, the wafer carrier is in an inverted orientationso that the semiconductor wafer rests in a space between the carrier andthe plate member. The riser of the first step has a very low height sothat the plate member limits the deflection of the wafer in a directiontowards the plate member as the wafer is demounted from the carrier.

In one aspect of the invention, the wafer demount receptacle's platemember is substantially circular, having a rim member including a firststep defining a first diameter, and a second step defining a seconddiameter greater than the first diameter.

In another aspect of the invention, the wafer demount receptacle hasunitary construction, being formed such as by casting or machining froma single piece of material. The material of construction may be anysuitable material such as quartz or sapphire, but preferably is formedfrom stainless steel or alumina.

A second device of the present invention comprises a wafer demount gasdistribution tool for removing a semiconductor wafer from a wafercarrier. The gas distribution tool comprises a gas shower head with agas inlet port and a substantially flat external face having anoperative gas distribution surface containing a pattern of through holeswhich serve as gas outlet ports. A peripheral sealing member providedaround a perimeter of the operative gas distribution surface, helps forma seal between the operative gas distribution surface and an opposingsurface against which the gas distribution tool is abutted.

In one aspect, the gas distribution tool's operative gas distributionsurface is substantially circular and the peripheral sealing member is atoroidal O-ring. With such a geometry, the gas distribution tool can beused in conjunction with the wafer demount receptacle for removing asemiconductor wafer from a wafer carrier. This is done by positioningthe gas distribution tool with its operative gas distribution surfaceand O-ring juxtaposed against the back side of wafer carrier mounted inthe wafer demount receptacle.

A first method in accordance with the present invention for debonding awafer from a wafer carrier includes the steps of providing a waferdemount receptacle having an upstanding rim member, placing a wafercarrier in an inverted position such that a portion of the rim membersupports a periphery of the wafer carrier, contacting the wafer carrierwith a solvent to promote separation of the semiconductor wafer from thewafer carrier, whereby an edge of the semiconductor wafer firstseparates from the wafer carrier and the wafer partially rests on theplate member, and then a remaining portion of the semiconductor waferseparates from the wafer carrier such that the semiconductor wafer restsentirely on the plate member.

A second method in accordance with the present invention for debonding awafer from a wafer carrier includes the steps of providing a waferdemount receptacle having an upstanding rim member, placing a wafercarrier in an inverted position such that a portion of the rim membersupports a periphery of the wafer carrier with a semiconductor wafermounted on the wafer carrier attached facing in a downward direction,contacting the wafer carrier with a solvent to promote separation of thesemiconductor wafer from the wafer carrier, fully dissolving theadhesive, placing the operative gas distribution surface of the gasdistribution tool in contact with the back surface of the carrier,flowing gas through the gas distribution tool, whereby gas bubbles areformed between the wafer carrier and the semiconductor wafer, an edge ofthe semiconductor wafer first separates from the wafer carrier and thewafer partially rests on the plate member, and then a remaining portionof the semiconductor wafer separates from the wafer carrier such thatthe semiconductor wafer rests entirely on the plate member.

In an aspect of either the first or the second method, the wafer carrierin abutment with the wafer demount receptacle is placed in a rack alongwith other such carrier/receptacle assemblies, and the rack is placed ina tank, prior to the step of contacting the wafer carriers with asolvent.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can better be understood from the followingdetailed description when read in conjunction with the attached figureswherein:

FIGS. 1a-1 c show conventional arrangements in which a semiconductorwafer is partially adhered to a carrier using various adhesive means;

FIG. 2a shows a plan view of a prior art carrier;

FIG. 2b shows the carrier of FIG. 2a having adhered thereto asemiconductor wafer;

FIG. 3a shows a plan view of a wafer demount receptacle in accordancewith the present invention;

FIG. 3b shows a detail of the plate member showing the through-holes andpedestals;

FIG. 3c shows a cross-section of FIG. 3a taken along line 3 c-3 c;

FIG. 3d shows a detail of the rim structure seen in FIG. 3a;

FIG. 4a shows a wafer demount assembly with the wafer fully affixed tothe wafer carrier;

FIG. 4b shows the wafer demount assembly of FIG. 4a with an edge of thewafer partially debonded from the wafer carrier;

FIG. 4c shows the wafer demount assembly of FIG. 4a with the wafer fullydebonded from the wafer carrier and resting on the wafer supportsurface;

FIG. 5a shows a top view of a wafer demount assembly rack;

FIG. 5b shows a side view of the wafer demount assembly rack of FIG.5a.;

FIG. 6a shows a cross-sectional view of a wafer demount gas distributiontool;

FIG. 6b shows a detail of the tool of FIG. 6a;

FIG. 7a shows a wafer demount assembly and wafer demount gasdistribution tool with the wafer fully adhered via liquid surfacetension to the wafer carrier;

FIG. 7b shows a wafer demount assembly and wafer demount gasdistribution tool with the wafer partially adhered via liquid surfacetension to the wafer carrier; and

FIG. 7c shows a wafer demount assembly and wafer demount gasdistribution tool with the wafer fully debonded from the wafer carrierand resting on the wafer support surface.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 3a shows a plan view of the wafer demount receptacle 200 of thepresent invention. The receptacle 200 preferably comprises a centralplate member 202 and an upstanding rim structure 204 formed along theperiphery thereof. Preferably, the receptacle has unitary construction,being cast or machined from a single piece of material, such asstainless steel, although other materials may also be used. In apreferred embodiment, the wafer demount receptacle is formed fromstainless steel or alumina.

As best seen in FIGS. 3b and 3 d, the plate member 202 of the receptaclecontains a pattern of through holes 220 interspersed among a pluralityof raised pedestals 222, each having a height p1. When a wafer isde-mounted from a carrier, the wafer falls onto these pedestals 222,which support the wafer at a multiplicity of discrete locations on thewafer's surface. Consequently, portions of the wafer which are notabutted by the pedestals 222 are exposed so as to facilitate themovement of a gas or fluid across the surface of the wafer.

Preferably, the holes 220 are centered on a first square grid of size 6mm×6 mm, and the pedestals 222 are centered a second square grid of thesame size which is interleaved with the first square grid, as seen inFIGS. 3a and 3 b. Preferably, the holes 220 have a 3 mm diameter andpedestals 222 have a 2 mm×2 mm square profile when viewed from the top,with height p1 being approximately 0.25 mm. While the above measurementsare preferred, other dimensions may also be suitable.

The rim structure 204 preferably does not extend around the entirecircumference of the receptacle 200, but rather is provided with atleast a pair of pick-up gaps 224 which are configured and dimensioned toaccommodate a pair of tweezers or other handling means used tomanipulate the receptacle.

As seen in FIGS. 3c-3 d, the plate member 202 has a thickness of t2which in a preferred embodiment is about 3 mm, although a wide range ofthickness, such as between 1.0 and 5.0 mm may suffice. Furthermore, therim structure 204 is stepped, with a first step 206 defining a firstdiameter d1, and a second step 208 defining a second diameter d2 greaterthan the first diameter d1. The receptacle 200 has an overall diameterd3. In a preferred embodiment, d1 is about 153 mm; d2 is 159.2 mm and d3is 175.0 mm, although they could be of other sizes, as well. It isnoteworthy, however, that d2 preferably is just slightly larger thantwice the radius (i.e., the diameter) of the carrier 150, for reasonsthat will become apparent below. It should be appreciated that thephysical dimensions of the demount fixture 200 scale with the size ofthe semiconductor wafer and carrier. Given a 150 mm diametersemiconductor wafer, for example, the demount fixture can have a firststep diameter which is slightly greater than 150 mm.

As also seen in FIG. 3d, the rim structure 204 provides the receptaclewith an overall height of h1, h1 preferably being about 6.25 mm. The rimstructure itself comprises a first step 206 having a height h2 relativeto the plate member, and a second step 208 having a height h3 relativeto the first step. In a preferred embodiment, the first step height h2is approximately 1.25 mm while the second step height h3 isapproximately 2.0 mm. The run 210 of the first step, which in apreferred embodiment has a length l1 of approximately 3.1 mm, serves asa carrier support surface during wafer de-mounting operations.

FIG. 4a shows a wafer demount assembly 400 in accordance with apreferred embodiment of the present invention. The wafer demountassembly 400 comprises a wafer demount receptacle 200 in contact with aperipheral abutment surface 426 of a carrier 406 to which is adhered asemiconductor wafer 402. In FIG. 4a the semiconductor wafer 402 isaffixed by means of an adhesive 404 to the carrier 406. Wafer 402,adhesive 404 and carrier 406 can be substantially similar to the wafer170, adhesive 172 and carrier 150 seen in FIG. 2. The wafer 402 has anactive wafer surface 410 on a first side, which may contain features andcircuits built thereon (not shown), and an inactive wafer surface 412 ona second side. The carrier has a bottom surface 420 on a first side anda top surface 422 on a second side. The top surface 422 of the carrieris comprised of two regions, a wafer contact surface 424, and aperipheral abutment surface 426. The inactive wafer surface 412 isbonded by means of the adhesive 404 to the wafer contact surface 424 ofthe carrier.

The body of the carrier 406 contains a pattern of through holes 428,which allows solvent to contact and dissolve the adhesive 404 during thedemounting step. The through holes 428 also promote the generation ofeddy currents in the solvent during the demounting step to help bringthe solvent in contact with the adhesive 404 at the interface betweenthe carrier's wafer contact surface 424 and the inactive wafer surface412.

FIG. 4a further shows the wafer carrier 406 in contact with the demountreceptacle 200 of the present invention. The peripheral abutment surface426 of the carrier abuts the demount receptacle 200 at a carrier supportsurface 250 formed on the run 210 of the first step 206. The waferdiameter is less than the diameter d1 of the first step 206, while thewafer carrier diameter is less than the diameter d2 of the second step208. Furthermore, the carrier thickness t1 preferably is less than theheight h3 of the riser of the second step 208 of the demountingreceptacle 200. The wafer thickness t3 is less than the height h2 of thefirst step 206 such that a first receiving gap g1 is formed between thewafer and the wafer receiving surface 222 and a second receiving gap g2is formed between the wafer and the receiving pedestals 222, g1>g2. In apreferred embodiment, gap g1 is less than about 2.0 mm.

To dislodge the wafer, the wafer demount assembly 400 preferably isoriented as shown in FIG. 4a, i.e., with the active surface of the waferfacing downward so as to fall onto the plate member and/or pedestals. Asolvent is then applied to the assembly, the solvent passing at leastpartially through the holes 428 formed in the carrier 406 to therebyattack the adhesive from the backside of the wafer 402. In this manner,the adhesive 404 is removed from the carrier-wafer interface as theassembly comes into contact with the solvent. In normal operation,during adhesive removal, the wafer 402 is partially adhered to thecarrier 406 at one instant, and then completely demounted from thecarrier 406 at another. The solvent acting on the back side of the wafer402, in combination with the force of gravity incrementally causesseparation of the wafer 402.

As seen in FIG. 4b, at some point, one edge of the wafer becomesdetached from the carrier 406, and the wafer slightly deforms under theweight of the separated edge. If this deformation proceeds unabated, thewafer may fracture before it is completely demounted from the carrier.However, the design of the present invention helps prevent waferbreakage during the demount process. Further deformation of a detachedportion of the wafer 402 is stopped when the wafer contacts the waferreceiving surface of the plate member 202 or, if present, one or morepedestals 222. Limiting the maximum bending in this manner helps preventwafer breakage. Furthermore, because the wafer 402 is contained withinthe space between the receptacle 200 and the carrier, it is protectedfrom external disturbances which may damage critical features or causecatastrophic fracture of the wafer.

Ultimately, as seen in FIG. 4c, the wafer 402 is fully demounted andrests on the pedestals, leaving space between the non-pedestalledportions of the plate member 202 and the wafer 402.

It should be noted that the peripheral abutment surface of the wafercarrier need not be entirely circumferential. For instance, the wafercarrier may be provided with a plurality of discrete tabscircumferentially spaced apart from one another along the periphery. Insuch case, the discrete tabs serves as peripheral abutment surfaces,supported by complementary surfaces formed on the rim member of thewafer demount receptacle. Such an arrangement can be advantageous, ifone wishes to maintain indexability of the wafer carrier relative to thewafer demount receptacle. Additionally, the peripheral abutment surfaceof the wafer carrier and the carrier support surface need not be planar,but may instead have complementary non-planar structures so as tofacilitate positioning the former onto the latter, such as in a dovetailfashion.

Multiple wafers can be demounted simultaneously by placing severaldemount assemblies 400 in a rack or cassette that is in turn placed in atank for contact with flowing solvent. FIG. 5a shows a top view of arack 500 with the outline of a wafer demount assembly 400 shown inphantom, and FIG. 5b shows a side view of the rack 500. The carriercomprises a substantially hollow frame configured with a plurality ofparallel slots 810. In the device shown in FIG. 5b, a total of 17 slotsare provided, although racks of other capacities may also be provided.Each slot has an opening sized to accommodate a single wafer demountassembly 400, which is inserted into the slot in the direction of thearrow A seen in FIG. 5a.

Once the wafer demount assemblies are loaded into the rack 500, the rackis lowered into a tank which is connected to a pump configured tocirculate solvent therein. The rate of solvent flow is controlled by thepump with the tank and connections preferably arranged such that thesolvent flows parallel to the surfaces of the wafer demount assemblies400. Eddy currents are generated in the solvent flow via interaction ofthe solvent with the holes 428 in the wafer demount receptacle 200. Theholes 428 in the wafer carrier also help to generate eddy currents whichaccelerate the dissolution of adhesive and hasten debonding the wafer.

FIG. 6a shows a wafer demount gas distribution tool 600 in accordancewith a preferred embodiment of the present invention. The gasdistribution tool 600 comprises a chamber 610 defined between a backingplate 602 and a contact plate 604 secured to one another by means ofscrews 606. A handle 640 is preferably attached to the backing plate602, to facilitate transport and operation of the gas distribution tool.The chamber 610 is provided with a gas inlet port 620 which, in apreferred embodiment, is formed in a lateral wall of the backing plate602 and is connectable to a pressurized gas source (not shown). Thecontact plate 604 has an internal surface 614 and an external, operativegas distribution surface 616 connected by a pattern of through holeswhich serve as gas outlet ports 630. The gas outlet ports preferablyhave a diameter which is between about 3 to 6 mm, and more preferablyabout 5 mm, although other dimensions may also be suitable.

When the gas distribution tool 600 is in use, a pressurized gas source(not shown) is connected to the gas inlet port, and the pressurized gasis forced through the gas outlet ports 630. A first, peripheral sealingmember, preferably formed as a first O-ring 612, protrudes from thecontact plate 604 from within a groove formed along a periphery of theoperative gas distribution surface 616, thereby encircling the latter. Asecond sealing member, formed as a second O-ring 608, forms a gas sealbetween the backing plate 602 and a contact plate 604 to retard, if notfully prevent, the escape of gases from chamber 610 at the interfacebetween the two plates.

While the embodiment of FIG. 6a shows separate backing plates andcontact plates, it is understood that a chamber having a backing plateand contact plate as portions of a single continuous material made, forexample, by injection molding, followed by any necessary machining orother operations, is also contemplated. In such case, then, the firstO-ring 608 and screws 606 would be unnecessary. Similarly, the presentinvention also contemplates a chamber formed by welding two or moreplates.

As seen in FIGS. 7a and 7 b, during the wafer demounting process, whenthe adhesive is fully dissolved by liquid solvent 414, a thin film ofsolvent may remain at the interface between the wafer and the carriercausing the wafer to remain adhered via solvent-induced surface tensionto the carrier 406. This surface tension may be overcome by using thegas distribution tool 600 of the present invention in conjunction withthe wafer demount receptacle 200.

Removal of the wafer from the carrier is accomplished by juxtaposing theoperative gas distribution surface 616 of the wafer demount gasdistribution tool with the backside 420 of the wafer carrier. Tofacilitate alignment between the two, the gas distribution tool isprovided with an alignment groove 618 which is formed along a perimeterof the external surface of the contact plate, and situated radiallyoutward of the peripheral sealing member 612. The alignment groove 618dovetails with the second step 208 of the wafer demount receptacle. Asshown in the detail of FIG. 6b, the perimeter alignment groove 618causes the second O-ring 612 of the gas distribution tool to align witha perimeter of the back side 420 of the wafer carrier in order to form agas seal between the gas distribution tool and wafer carrier.

When the gas distribution tool 600 and the backside 420 of the wafercarrier are in abutment, gas flowing into the chamber 610 exits throughholes 630, and is forced through carrier through holes 428 to thewafer-carrier interface. At the wafer-carrier interface, the forced gasdisplaces the solvent by forming small bubbles. The formation of gasbubbles and the concomitant displacement of solvent from thewafer-carrier interface (FIG. 7b) overcomes the liquid surface tensionand assists in completely removing the wafer from the carrier (FIG. 7c).The gas may be selected from the group consisting of argon, helium,nitrogen, air, or mixtures thereof, though other gases and mixtures maybe suitable. The gas pressure and flow are optimized and regulated toprevent breakage of the wafer by impact on the plate member 202 and/orpedestals 222.

It should be appreciated that while the wafer demount receptacle andoperative gas distribution surface 616 of the gas distribution tool arepreferably circular, their principal shapes are designed to conform tothe circular shape of a typical wafer carrier which itself supports acircular semiconductor wafer. The wafer demount receptacle and gasdistribution tool, therefore, may be of any suitable shape toaccommodate the geometry of a carrier onto which a semiconductor waferis bonded. Accordingly, if a semiconductor wafer is some other shape,say, triangular, a corresponding carrier may (but need not necessarily)be triangular, in which case the wafer demount receptacle and gasdistribution tool may also have a similar shape.

While the invention has been illustratively described herein withreference to specific aspects, features and embodiments, it will beappreciated that the utility and scope of the invention is not thuslimited and that the invention may readily embrace other and differingvariations, modifications and other embodiments. The invention thereforeis intended to be broadly interpreted and construed, as comprehendingall such variations, modifications and alternative embodiments, withinthe spirit and scope of the ensuing claims.

What is claimed is:
 1. A method of demounting at least one semiconductorwafer affixed to a wafer carrier, the method comprising: inverting thewafer carrier such that an active surface of the semiconductor waferfaces downwards; placing the wafer carrier onto a wafer demountreceptacle such that a peripheral abutment surface of the wafer carrierabuts, and is supported by, a carrier support surface formed on a rimmember of the wafer demount receptacle with a wafer receiving surface ofthe wafer demount receptacle opposing the active surface of thesemiconductor wafer, thereby forming a wafer demount assembly; andcontacting the wafer demount assembly with a solvent to promotedebonding the semiconductor wafer from the wafer carrier.
 2. The methodof claim 1, further comprising the step of placing the wafer demountassembly in a rack prior to contacting it with solvent.
 3. The method ofclaim 2, comprising the step of flowing a solvent in a directionsubstantially parallel to the active surface of the wafer when it iswithin the rack.
 4. The method of claim 3, comprising the step ofproviding the wafer receiving surface with a pattern of through-holeswhereby eddy currents are created, when the solvent is flowed in saiddirection.
 5. The method of claim 1, comprising the steps of: loading aplurality of wafer demount assemblies into a rack, placing the rack intoa tank; and introducing solvent into the tank to thereby simultaneouslydebond a plurality of wafers from a corresponding plurality of wafercarriers.
 6. The method of claim 1, further comprising the step ofdirecting pressurized gas against a back side of the wafer carrier. 7.The method of claim 6, comprising the step of forming a seal between awafer demount gas distribution tool from which the pressurized gasemerges, and a periphery of the back surface of the wafer carrier, asthe pressurized gas is directed against the back side of the wafercarrier.
 8. The method of claim 7, comprising the step of aligning thewafer demount gas distribution tool with the rim member of the wafer,prior to forming the seal.